Modules and Views → System Settings → System Notifications → Email Settings
Users in your organization can view, subscribe to, and un-subscribe from any system notification that is enabled. Users can subscribe to and un-subscribe from their system notifications using the My Notifications tab in the Tools module. You can subscribe every user in your organization to an enabled system notification by making it a default notification.
You may want to enable notifications for users, but not have those notifications be sent to a user's email account. In this case, when notifications are available, an icon will appear in the application toolbar.
Once you've configured and enabled system notifications, you have to specify which users and groups of users should receive email notifications. This is done from the Users tab in the Security tab.